# Support

**URL:** https://discourse.vtk.org/c/support/6.md?page=9

[Latest](https://discourse.vtk.org/latest.md) · [Categories](https://discourse.vtk.org/categories.md) · [Tags](https://discourse.vtk.org/tags.md)

**Page:** 10

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## [Getting tooltips and interaction from vtkContextView into vtkContextActor](https://discourse.vtk.org/t/getting-tooltips-and-interaction-from-vtkcontextview-into-vtkcontextactor/15652)

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**Author:** [@fraseyboo](https://discourse.vtk.org/u/fraseyboo)\
**Replies:** 2\
**Last updated:** [May 24, 2025, 11:08pm UTC](https://discourse.vtk.org/t/getting-tooltips-and-interaction-from-vtkcontextview-into-vtkcontextactor/15652 "2025-05-24T23:08:05Z")

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Hi everyone, I’m working on a project that relies on 2D & 3D plotting within the same visualiser, I’ve gotten pretty far with the inbuilt vtkCharts (vtkChartXY, vtkChartHistogram2D, etc.) and have them working within pa…

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## [vtknlohman build error](https://discourse.vtk.org/t/vtknlohman-build-error/15615)

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**Author:** [@dpugmire](https://discourse.vtk.org/u/dpugmire)\
**Replies:** 2\
**Last updated:** [May 24, 2025, 10:51pm UTC](https://discourse.vtk.org/t/vtknlohman-build-error/15615 "2025-05-24T22:51:56Z")

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I just downloaded 9.4.2 and trying to build with: c++ --version Apple clang version 17.0.0 (clang-1700.0.13.3) Target: arm64-apple-darwin24.4.0 Thread model: posix InstalledDir: /Library/Developer/CommandLineTools/u…

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## [VTK 9.5.0RC1: Question about vtkFastLabeledDataMapper](https://discourse.vtk.org/t/vtk-9-5-0rc1-question-about-vtkfastlabeleddatamapper/15653)

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**Author:** [@lukas](https://discourse.vtk.org/u/lukas)\
**Replies:** 0\
**Last updated:** [May 20, 2025, 7:48pm UTC](https://discourse.vtk.org/t/vtk-9-5-0rc1-question-about-vtkfastlabeleddatamapper/15653 "2025-05-20T19:48:47Z")

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I am trying the new vtkFastLabeledDataMapper in vtk9.5.0rc1. The documentation of the class sounds like it is a replacement of the vtkLabeledDataMapper, so I tried to adapt one of the VTK-Examples to use the vtkFastLabel…

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## [Please document off-by-one for modern NumberOfPolys](https://discourse.vtk.org/t/please-document-off-by-one-for-modern-numberofpolys/15651)

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**Author:** [@Chris\_Rorden](https://discourse.vtk.org/u/Chris_Rorden)\
**Replies:** 1\
**Last updated:** [May 20, 2025, 1:58pm UTC](https://discourse.vtk.org/t/please-document-off-by-one-for-modern-numberofpolys/15651 "2025-05-20T13:58:09Z")

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Traditional ASCII and binary legacy files are documented here and here, while examples and description of the modern XML VTK file is here. However, recent VTK code will read and write variations of the old format that a…

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## [How to avoid rendering ISO lines on surfaces](https://discourse.vtk.org/t/how-to-avoid-rendering-iso-lines-on-surfaces/15636)

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**Author:** [@samwit](https://discourse.vtk.org/u/samwit)\
**Replies:** 7\
**Last updated:** [May 20, 2025, 9:46am UTC](https://discourse.vtk.org/t/how-to-avoid-rendering-iso-lines-on-surfaces/15636 "2025-05-20T09:46:47Z")

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Hi vtk helpers, There’re always ISO lines on surfaces rendered, as highlighted below: Here’s my code: I can set the width of the lines by “props-\>SetLineWidth(3.0)”, but I cannot just disable it by assigning 0 t…

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## [matcap render support](https://discourse.vtk.org/t/matcap-render-support/15613)

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**Author:** [@samwit](https://discourse.vtk.org/u/samwit)\
**Replies:** 4\
**Last updated:** [May 20, 2025, 8:28am UTC](https://discourse.vtk.org/t/matcap-render-support/15613 "2025-05-20T08:28:08Z")

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Hi vtk helpers, Now I’m using vtk9.3. Does it support MatCap render? Or is there any alternative I can resort to? Thx a lot, Samuel

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## [vtkxxxxReader memory management](https://discourse.vtk.org/t/vtkxxxxreader-memory-management/15589)

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**Author:** [@Menga](https://discourse.vtk.org/u/Menga)\
**Replies:** 3\
**Last updated:** [May 19, 2025, 5:52am UTC](https://discourse.vtk.org/t/vtkxxxxreader-memory-management/15589 "2025-05-19T05:52:49Z")

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My program as a service, so it needs to continuously create different vtkxxxReader instances and read in files. However, I’m currently facing two issues. Even after the use of vtkxxxxReader has ended, the memory is not…

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## [vtkResliceImageViewer block mouse events](https://discourse.vtk.org/t/vtkresliceimageviewer-block-mouse-events/15645)

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**Author:** [@ivklb](https://discourse.vtk.org/u/ivklb)\
**Replies:** 0\
**Last updated:** [May 19, 2025, 2:14am UTC](https://discourse.vtk.org/t/vtkresliceimageviewer-block-mouse-events/15645 "2025-05-19T02:14:31Z")

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I want to overwrite the behavior of the default interactor style of vtkResliceImageViewer. I add some observers, and it works. But when I add a imagedata to vtkResliceImageViewer, all my observers won’t triggered. I tri…

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## [A question about Qt and vtk](https://discourse.vtk.org/t/a-question-about-qt-and-vtk/15637)

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**Author:** [@JXF](https://discourse.vtk.org/u/JXF)\
**Replies:** 1\
**Last updated:** [May 17, 2025, 12:51pm UTC](https://discourse.vtk.org/t/a-question-about-qt-and-vtk/15637 "2025-05-17T12:51:52Z")

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qt6 + vs 2022 + vtk9.4 I create a Qt6 project in Windows. There are two ways to choosed. The first is “Qt visual studio project”,i choose this option ,and write the code, and “RUN”,everything is OK. I call this Project …

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## [Building the official minimal Qt VTK example with Qt6 uses Qt5 instead](https://discourse.vtk.org/t/building-the-official-minimal-qt-vtk-example-with-qt6-uses-qt5-instead/15605)

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**Author:** [@MaxFleur](https://discourse.vtk.org/u/MaxFleur)\
**Replies:** 8\
**Last updated:** [May 17, 2025, 12:15pm UTC](https://discourse.vtk.org/t/building-the-official-minimal-qt-vtk-example-with-qt6-uses-qt5-instead/15605 "2025-05-17T12:15:10Z")

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I am trying to build the minimal Qt VTK app which is part of the official VTK examples (shown here). The C++ code for the app itself is mostly the same as specified via the link: #include \<QVTKOpenGLNativeWidget.h\> #inc…

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## [vtkClipPolyData has different behaviors in VTK 8.2.0 and in VTK 9.4.0](https://discourse.vtk.org/t/vtkclippolydata-has-different-behaviors-in-vtk-8-2-0-and-in-vtk-9-4-0/15626)

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**Author:** [@Ernesto\_Durante](https://discourse.vtk.org/u/Ernesto_Durante)\
**Replies:** 3\
**Last updated:** [May 16, 2025, 6:24pm UTC](https://discourse.vtk.org/t/vtkclippolydata-has-different-behaviors-in-vtk-8-2-0-and-in-vtk-9-4-0/15626 "2025-05-16T18:24:42Z")

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Hi, I am migrating my code from VTK 8.2.0 to VTK 9.4.0 and I have noticed (after spending some time debugging) that vtkClipPolyData behaves differently. The context is the following: I call vtkClipPolyData to clip wit…

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## [creating surgical guide](https://discourse.vtk.org/t/creating-surgical-guide/15581)

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**Author:** [@sreerajrs\_cdac](https://discourse.vtk.org/u/sreerajrs_cdac)\
**Replies:** 2\
**Last updated:** [May 16, 2025, 2:34pm UTC](https://discourse.vtk.org/t/creating-surgical-guide/15581 "2025-05-16T14:34:05Z")

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In the attached image, the rectangular cropped area on the surface is cleanly cut, and the sidewall boundary is extruded in a different direction, resulting in a visible thickness between the cropped surface and the side…

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## [QtCreator debug vtkObjects](https://discourse.vtk.org/t/qtcreator-debug-vtkobjects/15580)

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**Author:** [@NewPony](https://discourse.vtk.org/u/NewPony)\
**Replies:** 11\
**Last updated:** [May 15, 2025, 6:51pm UTC](https://discourse.vtk.org/t/qtcreator-debug-vtkobjects/15580 "2025-05-15T18:51:57Z")

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Hello, i use the QtCreator and Vtk under linux for developing a CMake-project. I build VTK in Debug and set the VTK\_DIR via /etc/environment. So when i use the QtCreator in debug mode i cant access any VtkOjects: A…

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## [Correct usage of SetPixelAspect() or possible workaround](https://discourse.vtk.org/t/correct-usage-of-setpixelaspect-or-possible-workaround/15602)

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**Author:** [@Sandor](https://discourse.vtk.org/u/Sandor)\
**Replies:** 2\
**Last updated:** [May 13, 2025, 8:14pm UTC](https://discourse.vtk.org/t/correct-usage-of-setpixelaspect-or-possible-workaround/15602 "2025-05-13T20:14:11Z")

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Hi, I would like to render my scene anisotropically , pixels stretched or compressed, the python vtk code below doesn’t seems to produce the expected behavior, no detectable distortion with any value specified. import …

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## [Volume rendering a vtkMultiBlockDataSet](https://discourse.vtk.org/t/volume-rendering-a-vtkmultiblockdataset/15616)

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**Author:** [@dpugmire](https://discourse.vtk.org/u/dpugmire)\
**Replies:** 0\
**Last updated:** [May 13, 2025, 6:43pm UTC](https://discourse.vtk.org/t/volume-rendering-a-vtkmultiblockdataset/15616 "2025-05-13T18:43:56Z")

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I have a dataset that is spatially broken up into blocks. However, I’m limited to how many blocks it can render. The openGL on MacM3 is old, 2.1, and GL\_MAX\_TEXTURE\_IMAGE\_UNITS is 16. I’m also running this on a newer l…

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## [A problem about choose one model](https://discourse.vtk.org/t/a-problem-about-choose-one-model/15611)

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**Author:** [@JXF](https://discourse.vtk.org/u/JXF)\
**Replies:** 2\
**Last updated:** [May 13, 2025, 10:11am UTC](https://discourse.vtk.org/t/a-problem-about-choose-one-model/15611 "2025-05-13T10:11:09Z")

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There is a request,a widget has two models,the code look like this vtkNew\<vtkRender\> renderA; //... vtkNew\<vtkRender\> renderB; //... renderA-\>SetViewport(0.0, 0.0, 0.5, 1.0); renderB-\>SetViewport(0.5, 0.0, 1.0, 1.0); …

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## [Orienting cylinder to point same way as camera](https://discourse.vtk.org/t/orienting-cylinder-to-point-same-way-as-camera/15586)

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**Author:** [@jimiheinonen](https://discourse.vtk.org/u/jimiheinonen)\
**Replies:** 3\
**Last updated:** [May 12, 2025, 8:39am UTC](https://discourse.vtk.org/t/orienting-cylinder-to-point-same-way-as-camera/15586 "2025-05-12T08:39:56Z")

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Hello! Is there a way to orient a cylinder (used for boolean operations) to point so that the ends are in the same direction as which the active camera is viewing? I don’t really understand how the orientation in the cam…

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## [Integrating VTK with PyQT](https://discourse.vtk.org/t/integrating-vtk-with-pyqt/15466)

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**Author:** [@safa\_harzali1](https://discourse.vtk.org/u/safa_harzali1)\
**Replies:** 8\
**Last updated:** [May 9, 2025, 4:42pm UTC](https://discourse.vtk.org/t/integrating-vtk-with-pyqt/15466 "2025-05-09T16:42:36Z")

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Hi. I am using vtk in my pyQt project. The issue I’m encountering is puzzling because the error doesn’t occur every time. Do you have any ideas on what might be causing this and how to diagnose it? Here is the relevant…

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## [Errorbar plotting in 2D (possibly using vtkPythonItem)](https://discourse.vtk.org/t/errorbar-plotting-in-2d-possibly-using-vtkpythonitem/15577)

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**Author:** [@fraseyboo](https://discourse.vtk.org/u/fraseyboo)\
**Replies:** 3\
**Last updated:** [May 8, 2025, 12:52pm UTC](https://discourse.vtk.org/t/errorbar-plotting-in-2d-possibly-using-vtkpythonitem/15577 "2025-05-08T12:52:22Z")

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So I’ve been playing around with the 2D plotting capabilities of VTK, in general they have pretty good coverage with the basics (scatter, line plot, bar charts & histograms) and the support for legends, titles and the to…

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## [Frozen renderer and when using vtk in PySide6 when only importing used vtkmodules](https://discourse.vtk.org/t/frozen-renderer-and-when-using-vtk-in-pyside6-when-only-importing-used-vtkmodules/15531)

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**Author:** [@rdbrn](https://discourse.vtk.org/u/rdbrn)\
**Replies:** 2\
**Last updated:** [May 8, 2025, 11:13am UTC](https://discourse.vtk.org/t/frozen-renderer-and-when-using-vtk-in-pyside6-when-only-importing-used-vtkmodules/15531 "2025-05-08T11:13:34Z")

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When I execute the script below I get a qt window with a non-responsive vtk display. It can be solved by enabling the “import vtk” line. using: Windows 11 Python 3.12 vtk 9.4.1 pyside6-essentials 6.8.2.1 Reproduce: …

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## [MPR Views Appearing Flipped (Mirror Image) in Custom FourPaneViewer Setup Using vtkResliceImageViewer](https://discourse.vtk.org/t/mpr-views-appearing-flipped-mirror-image-in-custom-fourpaneviewer-setup-using-vtkresliceimageviewer/15572)

<div class="topic-metadata">

**Author:** [@christeen](https://discourse.vtk.org/u/christeen)\
**Replies:** 3\
**Last updated:** [May 7, 2025, 2:58pm UTC](https://discourse.vtk.org/t/mpr-views-appearing-flipped-mirror-image-in-custom-fourpaneviewer-setup-using-vtkresliceimageviewer/15572 "2025-05-07T14:58:11Z")

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I’ve implemented a complete MPR viewer using the concept of FourPaneViewer with vtkResliceImageViewer. The viewer includes axial, coronal, sagittal and 3D views. However, I’m encountering a major issue: all three axial,c…

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## [How to create a mask from some ordered points?](https://discourse.vtk.org/t/how-to-create-a-mask-from-some-ordered-points/8292)

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**Author:** [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)\
**Replies:** 1\
**Last updated:** [May 7, 2025, 1:31pm UTC](https://discourse.vtk.org/t/how-to-create-a-mask-from-some-ordered-points/8292 "2025-05-07T13:31:31Z")

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I want to create a binary mask from some ordered points. For example, for the points: ps = \[ \[64, 64, 0\], \[128, 64, 0\], \[128, 128, 0\], \[64, 128, 0\], \] I hope it can create a binary mask which is agree …

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## [Exception thrown calling vtkColor3d GetColor3D in ReadOBJ example](https://discourse.vtk.org/t/exception-thrown-calling-vtkcolor3d-getcolor3d-in-readobj-example/7087)

<div class="topic-metadata">

**Author:** [@tiberius](https://discourse.vtk.org/u/tiberius)\
**Replies:** 6\
**Last updated:** [May 6, 2025, 2:20pm UTC](https://discourse.vtk.org/t/exception-thrown-calling-vtkcolor3d-getcolor3d-in-readobj-example/7087 "2025-05-06T14:20:42Z")

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I am working with C++ in VS 2019 Community Edition. I built and installed VTK-9.1.0.rc4. Afterwards, I wanted to try to verify using one of the examples. I grabbed the ReadOBJ example, configured, and built it. It thro…

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## [3D cursor and MIP](https://discourse.vtk.org/t/3d-cursor-and-mip/15569)

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**Author:** [@gunavg](https://discourse.vtk.org/u/gunavg)\
**Replies:** 0\
**Last updated:** [May 6, 2025, 6:43am UTC](https://discourse.vtk.org/t/3d-cursor-and-mip/15569 "2025-05-06T06:43:05Z")

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Hi I am working on FourPaneViewer sample project code. I would like to develop/integrate 3D cursor and MIP on 4th widget in FourPaneViewer application. How to develop 3D cursor and MIP in existing FourPaneViewer appli…

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## [Additive Selection not working for vtkScatterPlotMatrix](https://discourse.vtk.org/t/additive-selection-not-working-for-vtkscatterplotmatrix/15567)

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**Author:** [@roy](https://discourse.vtk.org/u/roy)\
**Replies:** 0\
**Last updated:** [May 5, 2025, 12:51pm UTC](https://discourse.vtk.org/t/additive-selection-not-working-for-vtkscatterplotmatrix/15567 "2025-05-05T12:51:14Z")

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I’m rendering a scatterplot matrix in VTK, but the additive selection (VTK: vtkScatterPlotMatrix Class Reference) is not working as it should. Only when I change the selection method for the big chart to SELECTION\_PLOTS…

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## [Compile error building VTK-9.3.0.rc1 on MacOS sequoia](https://discourse.vtk.org/t/compile-error-building-vtk-9-3-0-rc1-on-macos-sequoia/15528)

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**Author:** [@Tomasso](https://discourse.vtk.org/u/Tomasso)\
**Replies:** 6\
**Last updated:** [April 29, 2025, 5:43am UTC](https://discourse.vtk.org/t/compile-error-building-vtk-9-3-0-rc1-on-macos-sequoia/15528 "2025-04-29T05:43:42Z")

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Building VTK-9.3.0.rc1 on MacOS Sequoia, running xcode Version 16.3 (16E140). Following compile error occurs: \[ 1%\] Building C object ThirdParty/zlib/vtkzlib/CMakeFiles/zlib.dir/zutil.c.o cd /Users/oreilly/VTK-9.3.0.rc…

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## [The rendering performance of VTK is lower than that of QOpenGLWidget. How can I improve VTK's display performance?](https://discourse.vtk.org/t/the-rendering-performance-of-vtk-is-lower-than-that-of-qopenglwidget-how-can-i-improve-vtks-display-performance/15518)

<div class="topic-metadata">

**Author:** [@Ynnnnnn](https://discourse.vtk.org/u/Ynnnnnn)\
**Replies:** 10\
**Last updated:** [April 28, 2025, 6:10pm UTC](https://discourse.vtk.org/t/the-rendering-performance-of-vtk-is-lower-than-that-of-qopenglwidget-how-can-i-improve-vtks-display-performance/15518 "2025-04-28T18:10:00Z")

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The rendering performance of VTK is lower than that of QOpenGLWidget. How can I improve VTK’s display performance? Background: I am using Qt + VTK to display point cloud data, with the final deployment on Linux (but te…

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## [vtkContext2D : what strategies to improve perfs ?](https://discourse.vtk.org/t/vtkcontext2d-what-strategies-to-improve-perfs/15543)

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**Author:** [@Olivier](https://discourse.vtk.org/u/Olivier)\
**Replies:** 6\
**Last updated:** [April 28, 2025, 4:41pm UTC](https://discourse.vtk.org/t/vtkcontext2d-what-strategies-to-improve-perfs/15543 "2025-04-28T16:41:59Z")

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Hi friends, I’m using vtkContext2D to draw an entire scene made of lines, polygons, texts. Works great. I’m starting to work with larger scenes, and I’m issuing very bad performance drops when the number of primitives…

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## [What is the easiest way to clip a vtkOutlineFilter?](https://discourse.vtk.org/t/what-is-the-easiest-way-to-clip-a-vtkoutlinefilter/15550)

<div class="topic-metadata">

**Author:** [@uv382](https://discourse.vtk.org/u/uv382)\
**Replies:** 1\
**Last updated:** [April 28, 2025, 2:25pm UTC](https://discourse.vtk.org/t/what-is-the-easiest-way-to-clip-a-vtkoutlinefilter/15550 "2025-04-28T14:25:17Z")

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I would like to show only the corners of the outline shown with a vtkOutlineFilter: My thought was that I could first create the vtkOutlineFilter algorithm, and then “subtract” the parts that I don’t want using some …

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## [Geometry in ICP registration](https://discourse.vtk.org/t/geometry-in-icp-registration/15541)

<div class="topic-metadata">

**Author:** [@maedeh\_kafiyan\_safar](https://discourse.vtk.org/u/maedeh_kafiyan_safar)\
**Replies:** 6\
**Last updated:** [April 28, 2025, 2:09pm UTC](https://discourse.vtk.org/t/geometry-in-icp-registration/15541 "2025-04-28T14:09:27Z")

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I am currently using the Iterative Closest Point (ICP) algorithm provided by the VTK library for my 3D bone model. I have a set of 60 points from one part of the object, and I am trying to register them. Below is an imag…

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